External Anatomy

Ear and Ear Lobe

Ear:

• Embryos can develop ears within the first two weeks

• After a chicken is born, its hearing is critical because the hen uses auditory systems to teach the offspring what to eat and what to not eat

• Chicken ears have three parts: an outer ear, an inner ear and an middle ear

• There is a single cartilage in the chicken ear known as the "columella"

Ear Lobe:

• The ear lobe is a is a modification of skins

• Its located below the opening of the ear

• Chickens tend to have different colored ear lobes

Combs and Wattle:

• These tend to vary in size and shape

• Chickens control their body temperature with their wattle and combs

• Size and color are based on sex hormones- they signifiy sexual maturity and attraction

Molting

• Molting is the shedding of feathers to make room for new feathers

• Chickens molt at least once a year

• Hens usually molt when they stop laying eggs in the winter

• Molting happens in a specific order: head, neck, body, wings, tail

• The picture shows the growth of the new feathers coming in through keratinization

Uropygial Gland (Preen Gland)

• This is a large sebaceous gland

• This is covered by tail feathers

• This secretes oil to be distributed throughout the feathers

• This helps waterproof their feathers

• It also helps fight antimicrobial activity against feather-degrading bacteria